Added tests for paths logic in Executor

Added 3 new tests for ScriptExecutor:
* ShouldAddReferenceToEachDestinationFile
* ShouldNotCopyFilesInPathIfLastWriteTimeEqualsLastWriteTimeOfFileInBin
* ShouldCopyFilesInPathIfLastWriteTimeDiffersFromLastWriteTimeOfFileInBin

With this most of the current functionality of the ScriptExecutor is tested.